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Long-Term Intersite Decomposition Experiment Team (LIDET) Project The last litter bag collected at HJ Andrews was tag number 1.

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Presentation on theme: "Long-Term Intersite Decomposition Experiment Team (LIDET) Project The last litter bag collected at HJ Andrews was tag number 1."— Presentation transcript:

1 Long-Term Intersite Decomposition Experiment Team (LIDET) Project The last litter bag collected at HJ Andrews was tag number 1

2 Synthesis Approach  Pre-planned experiment  Team-designed  Centrally coordinated  Standardized methods  Predetermined spatial and temporal limits

3 LIDET Establishment NSF Workshop Woods Hole Marine Biological Laboratory, May 1989  Recognition of greater value in joint project with common measurements  Realization that not all decomposition controlling factors can be studied  Discussion of investigator-related issues  Clearly define role of project participants  Develop equitable strategy for publication credit  Balance standardization and central control against needs of individual sites

4 Study Description  Test the effect of substrate quality and macroclimate on long-term decomposition and nutrient dynamics  10 year experiment  28 sites (17 LTER sites)  Long-term, broad-scale, multi-site, multi- investigator experiment to provide regional and global perspective

5 Distribution of LIDET Sites Wide array of ecosystem types Annual precipitation 230-4000 mm per year Mean annual air temperature –7 to 26 degrees C

6 Distribution of sites across climatic gradient

7 Formation of LIDET Team  Field Collaborators (1 per site)  Manages experiment at local level  Provides background information  Central Analysis Group (central site)  Coordinates chemical analysis and data processing  Manages long-term data and sample archive  Conducts preliminary data analysis  Modelers ( CENTURY, GEM, GENDEC, DODMOD )  Examine process models  Test to determine most general structures and assumptions

8 Methodology  Generally accepted methods were easy to standardize - Litter bags and dowels  Initially collect 9 standard litters and 28 wildcard litters  3 Fine roots - (graminoid, hardwood, conifer)  6 Leaf litter - (lignin/nitrogen ratio 6 to 43)  1 Wildcard (leaf litter) from each site  1 Wooden dowel (above/below ground decomposition)  Centrally prepare and distribute all materials to each site  Collect samples annually for 10 years  4 reps for each species, site, time  Centrally analyze for chemical composition  Near-infrared reflectance (NIR) spectroscopy (Total nitrogen, lignin, cellulose)

9 Continental Level Site Level Geographical Distribution of Sampling Scheme Replicate Level

10 Litterbags are distributed throughout an array of ecosystems

11 Wooden Dowels measure both above- and belowground decomposition

12 Initial Litter Collection Standard Litters (9 sites) “Wildcard” Litters (28 sites) Information and Materials Flow in LIDET “Litterbag Central” Litterbags constructed Data entry & Chemical analysis Data management Litterbags Installed (once) Litter Collected (10 times) Data Update (10 times) Field Experiments at 28 Sites

13 Litterbags at various stages of decomposition

14 Shared Data and Credit  Central site annually provides data to each site  Site has one-year for site-specific publishing  After one year, site data is available for intersite synthesis under joint LIDET authorship or modeling  Only published data is available to the public (Special requests have been honored)  In the end, all data will be public, and the database will be maintained in a long-term data repository at the OSU Forest Science Data Bank (FSDB)

15 Data Processing and Information Management  PI initially designed data structures  Data and metadata structures conformed to FSDB protocols  ASCII data and SAS processing routines  16,000+ samples provided logistical challenge  Relational database interface developed  Generates site forms annually indicating litter bags to remove  Provides data entry screens  Merges analytical data into database  Prints reports and sample labels  Conducts preliminary calculations of decay rate and % mass

16 Approaches to QA/QC  Central preparation of materials  Initial estimation of oven-dried litter weight  Comprehensive instructions sent originally  Instructions resent annually  Data sent annually for site to review and keep  Dowel provides link to other decomposition studies

17 Lab and Data QA/QC  Laboratory  Initial evaluation and comparison of laboratories  Consistent laboratory and methods  Wet chemistry calibration of NIR analyses  Spot checking of site weight measurements  Data  Data codes were provided to document questionable data  Percent remaining mass data plotted to track outliers  Catalog of samples tracked in relational database  Visual inspection

18 Obstacles to Intersite Synthesis  Change is constant – “Assume nothing!”  Over 10 years personnel changes, instructions lost, maps lost  Study sites not protected  Fires, forestry projects, accidents  Logistical problems  Established infrastructure at sites  17 of 28 sites being LTER sites minimized cost  Communication  Development of electronic email network was great improvement

19 Obstacles to Preparing LIDET Data  Data processing and analysis of 16,000+ samples pose logistical problems  Sites do not always follow instructions  Site information is generally not available  Climate data requests were frequently ignored  Feedback from site reviews of annual data was lacking or incomplete – “it’s wrong”

20 Current LIDET Status  2001 is final year of litter bag removal  Total experiment duration will be 13-14 years (1 year setup and 2-3 years data cleanup and analysis)  25 of 28 sites will complete the experiment  Resource largely unpublished  NCEAS-like workshop under consideration (possible Springer-Verlag book on decomposition)

21 Intersite Project Success  Interesting ideas or hypotheses are essential to attract investigators  Increased funding to conduct many measurements needed  Strong communication among scientists and coordination of activities are essential to produce comprehensive tests of hypotheses

22 Benefits of Approach  Places individual site results in a larger context  Allows access to novel analytic methods (NIR)  Greater sense of participation on global change research  Advantages of a team-designed, simultaneously- conducted experiment vs. “post”-harmonization approach  Avoids limitations due to disparities in geographic distribution, study duration, and methodologies  “Synthesis before, not after, the fact!”

23 Mark Harmonization in action

24 Special thanks to Mark Harmon and Becky Fasth Additional thanks to Suzanne Remillard and Jay Sexton Citation: Long-Term Intersite Decomposition Experiment Team (LIDET). 1995. Meeting the challenge of long-term, broad-scale ecological experiments. Seattle, WA: LTER Network Office; Publication No. 19. 23 p. LTER- and NSF-supported through Ecosystem Studies Grants

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